1. Field of the Invention
The present invention relates to a compound (triple reuptake inhibitor) capable of inhibiting reuptake of the neurotransmitters, dopamine, serotonin, and norepinephrine at the same time, and an antidepressant including the same.
2. Description of the Related Art
Depression, namely, depressive disorder means a disease that is characterized by loss of interest and sadness as major symptoms and causes various cognitive, emotional, and physical symptoms, leading to impairment of normal function. It has been estimated that the lifetime prevalence of depressive disorder is 15%, and in particular, 25% in women. Depressive disorder is a serious illness causing emotional, cognitive, physical and behavioral changes.
The etiology of depression is complex, resulting from interactions of various genes, and epigenetic, genetic, and environmental factors, rather than a single cause. Consequently, impairment in feelings occurs, leading to emotional disorders.
Compounds currently used for depression exhibit great therapeutic effects on other symptoms caused by a pathophysiologic substance, such as memory loss, desynchronization, and pain, as well as emotional impairment in depression.
Drugs typically used for other major mental or neurological disorders show their efficacy through a variety of neural mechanisms distributed throughout the brain. Similarly, pharmacological, anatomical, and neuropsychiatric approaches to alleviation of depression cannot be made to exhibit efficacy through one mechanism of action.
Since the antituberculosis drug iproniazid was proved to show an anti-depressant effect as a monoamine oxidase inhibitor (MAOIs), modern antidepressants have been actively developed. In the early 1950s, an antihistamine, chlorpromazine was developed as an antipsychotic agent, and its therapeutic effect on schizophrenia was proved. Similarly, since imipramine was developed as an antihistamine by Geigy Drug Co. in Switzerland, 1955, active development of antidepressants has begun. These discoveries brought about development of tricyclic antidepressants (TCA), and many TCAs such as nortriptyline, doxepin, clomipramine or the like have come into use, in addition to amitriptyline or desipramine having a modified tricyclic structure.
Later, second- and third-generation antidepressants have been developed, and tetracyclic compounds such as maprotiline and amoxapine that are similar in the structure and efficacy were commercialized in the early 1980s, which are also called heterocyclics.
In the 1980s, one of the selective serotonin reuptake inhibitors (SSRIs), Prozac was developed and used as an effective therapeutic agent. However, it has been reported that Prozac causes anticholinergic side effects of dry mouth, constipation, urinary retention, blurred vision, impotence or the like, acts on the cardiovascular system to considerably affect blood pressure, pulse, cardiac conduction or the like, blocks 1-adrenergic receptors to cause orthostatic hypotension, and has antihistamine effects that explain its sedative action.
Current antidepressant agents include selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, selective norepinephrine reuptake inhibitors, dopamine and norepinephrine reuptake inhibitors (DNRI), noradrenergic and specific serotonergic antidepressants (NaSSA), serotonin-antagonists/serotonin reuptake inhibitors (SARI), selective serotonin reuptake enhancers (SSRE) or the like.
These antidepressant agents currently used in the treatment show low remission rates. Thus, it is difficult to achieve sufficient therapeutic effects by using these drugs. For this reason, the antidepressant market is expected to reduce. In order to overcome the low remission rate, it is required to develop a new concept of therapeutic agent.
Representative side effects of the current therapeutic antidepressants are sexual dysfunction and weight gain, and development of new antidepressants that are able to overcome these side effects is expected to open a new market.
One of other major problems is that the current therapeutic antidepressants have a lag-time of several weeks to several months until its onset of action after drug administration. Improvement of efficacy by reducing the lag-time is also an important issue in the development of antidepressants.
For proper selection and efficacy improvement of antidepressant agents, personalized therapy must be provided through the investigations of new biomarkers for major depressive disorder.
Owing to their mechanism of action, antidepressant agents can be also applied to other neuropsychiatric disorders such as neurogenic pain, bipolar disorder or the like. Thus, the development of related studies makes it possible to achieve external extension of the antidepressant market.